NASA/ESA Cassini-Huygens Will Unlock Saturn’s Secrets
The international Cassini-Huygens mission is poised to begin an
extensive tour of
Saturn, its majestic rings and 31 known moons. After a nearly
seven-year journey,
Cassini is scheduled to enter orbit around Saturn at 7:30 p.m. PDT
(10:30 p.m. EDT) June 30, 2004.
“The Saturn system represents an unsurpassed laboratory, where we can
look for
answers to many fundamental questions about the physics, chemistry and
evolution of
the planets and the conditions that give rise to life,” said Dr. Ed
Weiler, associate
administrator for space science at NASA Headquarters, Washington, D.C.
Launched Oct. 15, 1997, on a journey covering 3.5 billion kilometers
(2.2 billion miles),
Cassini is the most highly instrumented and scientifically capable
planetary spacecraft
ever flown. It has 12 instruments on the Cassini orbiter and six more
on the Huygens
probe. The mission represents the best technical efforts of 260
scientists from the
United States and 17 European nations. The cost of the Cassini mission
is approximately
$3 billion.
The Cassini-Huygens mission is a four-year study of Saturn. The 18
highly sophisticated
science instruments will study Saturn’s rings, icy satellites,
magnetosphere and Titan, the planet’s largest moon.
For the critical Saturn orbit insertion maneuver, the spacecraft will
fire its main engine
for 96 minutes. The maneuver will reduce Cassini’s speed and allow it
to be captured
into orbit as a satellite of Saturn. Cassini will pass through a gap
between two of
Saturn’s rings, called the F and G rings. Cassini will swing close to
the planet and
begin the first of 76 orbits around the Saturn system. During
Cassini’s four-year mission,
it will execute 52 close encounters with seven of Saturn’s 31 known
moons.
There are risks involved with orbit insertion, but mission planners
have prepared for
them. There is a backup engine in case the main engine fails. The
region of passage
through the ring plane was searched for hazards with the best Earth-
and space-based
telescopes.
Particles too small to be seen from Earth could be fatal to the
spacecraft, so Cassini
will be turned to use its high-gain antenna as a shield against small
objects.
Saturn is the sixth planet from the sun. It is the second largest
planet in our solar system,
after Jupiter. The planet and its ring system serve as a miniature
model for the disc
of gas and dust surrounding the early Sun that formed the planets.
Detailed knowledge
of the dynamics of interactions among Saturn’s elaborate rings and
numerous moons
will provide valuable data for understanding how each of the solar
system’s planets
evolved.
The study of Titan, Saturn’s largest moon, is one of the major goals
of the mission.
Titan may preserve, in deep-freeze, many of the chemical compounds
that preceded
life on Earth. Cassini will execute 45 flybys of Titan, coming as
close as approximately
950 kilometers (590 miles) above the surface. This will permit
high-resolution mapping
of the moon’s surface with an imaging radar instrument, which can see
through the
opaque haze of Titan’s upper atmosphere.
“Titan is like a time machine taking us to the past to see what Earth
might have been
like,” said Dr. Dennis Matson, Cassini project scientist at NASA’s Jet
Propulsion
Laboratory, Pasadena, Calif. “The hazy moon may hold clues to how the
primitive
Earth evolved into a life-bearing planet.”
On Dec. 25, 2004 (Dec. 24 in U.S. time zones) Cassini will release the
wok-shaped
Huygens probe on its journey toward Titan. Huygens will be the first
probe to descend
to the surface of a moon of another planet. It will also make the most
distant descent
by a robotic probe ever attempted on another object in the solar
system. On Jan. 14,
2005, after a 20-day ballistic freefall, Huygens will enter Titan’s
atmosphere. It will
deploy parachutes and begin 2.5 hours of intensive scientific
observations. The
Huygens probe will transmit data to the Cassini spacecraft, which will
relay the information back to Earth.
JPL designed, developed and assembled the Cassini orbiter. The
European Space
Agency managed the development of Huygens and is in charge of
operations of the
probe from its control center in Darmstadt, Germany. The Italian Space
Agency provided
the high-gain antenna, much of the radio system and elements of
several of
Cassini’s science instruments. JPL manages the overall program for
NASA’s Office of
Space Science, Washington, D.C.
For information about the Cassini-Huygens mission to Saturn and Titan
on the Internet,
visit: http://www.nasa.gov/cassini or
http://www.esa.int/Cassini-Huygens .
